Verizon Wireless said it would no longer sign exclusive handset contracts that bar smaller U.S. companies from selling a product for more than six months.

Verizon has exclusivity deals to sell the BlackBerry Storm and other phones, which helps the company attract customers. On the other hand, smaller companies have complained the deals put them at a competitive disadvantage. Sen. Herb Kohl, D-Wisc., has also asked federal regulators and the Department of Justice to look into the deals on potential antitrust issues, InformationWeek reported.

In a letter sent to the House Committee on Energy and Commerce, Verizon said, "Effective immediately for small wireless carriers (those with 500,000 customers or less), any new exclusivity arrangement we enter with handset makers will last no longer than six months -- for all manufacturers and all devices."

At a recent hearing, U.S. Cellular President and Chief Executive Officer Jack Rooney said he could tolerate exclusivity deals of moderate length -- months, not years, PC World reported.

AT&T, which has sold Apple's iPhone exclusively for two years, is not likely to follow Verizon's lead in granting smaller companies a break, PC World said.